get_bkg_chisqr_plot
- sherpa.astro.ui.get_bkg_chisqr_plot(id: IdType | None = None, bkg_id: IdType | None = None, recalc=True)
Return the data used by plot_bkg_chisqr.
- Parameters:
id (int, str, or None, optional) – The data set that provides the data. If not given then the default identifier is used, as returned by
get_default_id
.bkg_id (int, str, or None, optional) – Identify the background component to use, if there are multiple ones associated with the data set.
recalc (bool, optional) – If
False
then the results from the last call toplot_bkg_chisqr
(orget_bkg_chisqr_plot
) are returned, otherwise the data is re-generated.
- Returns:
chisqr – An object representing the data used to create the plot by
plot_bkg_chisqr
.- Return type:
a
sherpa.astro.plot.BkgChisqrPlot
instance- Raises:
sherpa.utils.err.ArgumentErr – If the data set does not contain PHA data.
sherpa.utils.err.IdentifierErr – If the
bkg_id
parameter is invalid.sherpa.utils.err.ModelErr – If no model expression has been created for the background data.
See also
get_bkg_delchi_plot
Return the data used by plot_bkg_delchi.
get_bkg_ratio_plot
Return the data used by plot_bkg_ratio.
get_bkg_resid_plot
Return the data used by plot_bkg_resid.
plot_bkg_chisqr
Plot the chi-squared value for each point of the background of a PHA data set.
Examples
>>> bplot = get_bkg_chisqr_plot() >>> print(bplot)
>>> get_bkg_chisqr_plot('jet', bkg_id=1).plot() >>> get_bkg_chisqr_plot('jet', bkg_id=2).overplot()